[PATCH 5.15 587/846] drm/etnaviv: consider completed fence seqno in hang check

From: Greg Kroah-Hartman
Date: Mon Jan 24 2022 - 18:08:52 EST


From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>

[ Upstream commit cdd156955f946beaa5f3a00d8ccf90e5a197becc ]

Some GPU heavy test programs manage to trigger the hangcheck quite often.
If there are no other GPU users in the system and the test program
exhibits a very regular structure in the commandstreams that are being
submitted, we can end up with two distinct submits managing to trigger
the hangcheck with the FE in a very similar address range. This leads
the hangcheck to believe that the GPU is stuck, while in reality the GPU
is already busy working on a different job. To avoid those spurious
GPU resets, also remember and consider the last completed fence seqno
in the hang check.

Reported-by: Joerg Albert <joerg.albert@xxxxxx>
Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Reviewed-by: Christian Gmeiner <christian.gmeiner@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 1 +
drivers/gpu/drm/etnaviv/etnaviv_sched.c | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
index 1c75c8ed5bcea..85eddd492774d 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -130,6 +130,7 @@ struct etnaviv_gpu {

/* hang detection */
u32 hangcheck_dma_addr;
+ u32 hangcheck_fence;

void __iomem *mmio;
int irq;
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
index feb6da1b6cebc..bbf391f48f949 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
@@ -107,8 +107,10 @@ static enum drm_gpu_sched_stat etnaviv_sched_timedout_job(struct drm_sched_job
*/
dma_addr = gpu_read(gpu, VIVS_FE_DMA_ADDRESS);
change = dma_addr - gpu->hangcheck_dma_addr;
- if (change < 0 || change > 16) {
+ if (gpu->completed_fence != gpu->hangcheck_fence ||
+ change < 0 || change > 16) {
gpu->hangcheck_dma_addr = dma_addr;
+ gpu->hangcheck_fence = gpu->completed_fence;
goto out_no_timeout;
}

--
2.34.1